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Cellphone Use Tied to Changes in Brain Activity

Researchers from the National Institutes of Health have found that less than an hour of cellphone use can speed up brain activity in the area closest to the phone antenna, raising new questions about the health effects of low levels of radiation emitted from cellphones.

The researchers, led by Dr. Nora D. Volkow, director of the National Institute on Drug Abuse, urged caution in interpreting the findings because it is not known whether the changes, which were seen in brain scans, have any meaningful effect on a person’s overall health.

“The study is important because it documents that the human brain is sensitive to the electromagnetic radiation that is emitted by cellphones,” Dr. Volkow said. “It also highlights the importance of doing studies to address the question of whether there are — or are not — long-lasting consequences of repeated stimulation, of getting exposed over five, 10 or 15 years.”

Although preliminary, the findings are certain to reignite a debate about the safety of cellphones. A few observational studies have suggested a link between heavy cellphone use and rare brain tumors, but the bulk of the available scientific evidence shows no added risk. Major medical groups have said that cellphones are safe, but some top doctors, including the former director of the University of Pittsburgh Cancer Center and prominent neurosurgeons, have urged the use of headsets as a precaution.

Dr. Volkow said that the latest research is preliminary and does not address questions about cancer or other heath issues, but it does raise new questions about potential areas of research to better understand the health implications of increased brain activity resulting from cellphone use.

“Unfortunately this particular study does not enlighten us in terms of whether this is detrimental or if it could even be beneficial,” Dr. Volkow said. “It just tells us that even though these are weak signals, the human brain is activated by them.”

When asked to comment on the latest study, the leading industry trade group, CTIA – The Wireless Association, released a statement emphasizing recent studies that have shown no elevated cancer risk associated with cellphone use.

“The peer-reviewed scientific evidence has overwhelmingly indicated that wireless devices, within the limits established by the F.C.C., do not pose a public health risk or cause any adverse health effects,” said John Walls, vice president of public affairs for the trade group, adding that leading global health groups “all have concurred that wireless devices are not a public health risk.”

But the new research differed from the large observational studies that have been conducted to study cellphone use. In Dr. Volkow’s study, the researchers used brain scans to directly measure how the electromagnetic radiation emitted from cellphones affected brain activity..

The randomized study, conducted in 2009, asked 47 participants to undergo positron emission tomography — or PET — scans, which measure brain glucose metabolism, a marker of brain activity. Each study subject was fitted with a cellphone on each ear and then underwent two 50-minute scans.

During one scan, the cellphones were turned off, but during the other scan, the phone on the right ear was activated to receive a call from a recorded message, although the sound was turned off to avoid auditory stimulation.

Whether the phone was on or off did not affect the overall metabolism of the brain, but the scans did show a 7 percent increase in activity in the part of the brain closest to the antenna when the right phone was turned on. The finding was highly statistically significant, the researchers said. They said the activity was unlikely to be associated with heat from the phone because it occurred near the antenna rather than where the phone touched the head.

In the past, any concerns about the health effects of cellphones have been largely dismissed because the radiofrequency waves emitted from the devices are believed to be benign. Cellphones emit nonionizing radiation, waves of energy that are too weak to break chemical bonds or to set off the DNA damage known to cause cancers. Scientists have said repeatedly that there is no known biological mechanism to explain how nonionizing radiation might lead to cancer or other health problems.

But the new study opens up an entirely new potential area of research. Although an increase in brain glucose metabolism happens during normal brain function, the question is whether repeated artificial stimulation as a result of exposure to electromagnetic radiation might have a detrimental effect.

Although speculative, one theory about how an artificial increase in brain glucose metabolism could be harmful is that it could potentially lead to the creation of molecules called free radicals, which in excess can damage healthy cells. Or it may be that repeated stimulation by electromagnetic radiation could set off an inflammatory response, which studies suggest is associated with a number of heath problems, including cancer.

Among cancer researchers and others interested in the health effects of cellphones, the study, listed in the medical journal under the heading “Preliminary Communications,” was met with enthusiasm because of the credibility of the researchers behind it and the careful methods used.

“It’s a high-quality team, well regarded, and if nothing else they’re showing that radiation is doing something in the brain,” said Louis Slesin, editor of Microwave News, a newsletter on the health effects of electromagnetic radiation. “The dogma in the cellphone community says that it doesn’t do anything. What she’s shown is that it does do something, and the next thing to find out is what it’s doing and whether it’s causing harm.”

Dr. Ronald B. Herberman, former director of the Pittsburgh Cancer Institute and now chief medical officer for the Intrexon Corporation, a biotechnology company in Germantown, Md., said, “I think it’s a very well-designed study, and they have clearly shown that there is biologic activity being induced in the nerve cells in the region where the antenna is the closest.” Dr. Herberman said skeptics about the risks of cellphones have focused on the fact that the type of radiation they emit is too weak to break chemical bonds and cannot plausibly be implicated in cancer. However, the new research suggests a potentially different pathway for cancer and other health problems to develop.

“I think it’s an important new direction to go in for biologists to start delving deeper into sorting out what might be going on,” Dr. Herberman said.

In an editorial accompanying the Journal article, Henry C. Lai, a University of Washington professor of bioengineering who has long raised concerns about cellphone safety, said he hoped the data would broaden the focus of cellphone research and health.

“The bottom line is that it adds to the concern that cellphone use could be a health hazard,” said Dr. Lai. “Everybody is worried about brain cancer, and the jury is still out on that question. There are actually quite a lot of studies showing cellphone radiation associated with other events, like sleep disturbances. But people have not been paying a lot of attention to these other types of studies.”

Dr. Volkow said future research may even show that the electromagnetic waves emitted from cellphones could be used to stimulate the brain for therapeutic reasons. She said the research should not set off alarms about cellphone use because simple precautions like using a headset or earpiece can alleviate any concern.

“It does not in any way preclude or decrease my cellphone utilization,” she said.

From the look at the pictures, the increased activity appears at multiple areas of the brain, equally in both hemispheres. Admittedly, I’m not an expert at reading and interpreting PET scans, but what I see doesn’t match the conclusions as stated.

FROM TPP — Scans are tough to read, and I’m not an expert either. But the study authors didn’t see any statistically significant changes in whole brain activity — that doesn’t mean we might not observe some on the scans. But the relevant part is on the far right — you’l see some red orange areas — that was the high level of activation near the antenna site.

If correctly reported, the design of the study is questionable. A cell phone that is only receiving doesn’t emit as much electromagnetic radiation as one that is transmitting. That is, if you aren’t talking — and here the subjects were only listening to a recorded message — then your cell phone isn’t transmitting nearly as much as if you were talking. I defer to a telecom engineer, and maybe the researchers should, but based on what is said here, I doubt that there was much electromagnetic radiation coming from the cell phone. Certainly there wouldn’t be as much as if the subjects were talking and the phone were transmitting their conversation. Cell phones are like automated walkie-talkies. Unless you push the button to talk, they don’t transmit.
FROM TPP — It’s true that because the person was not transmitting, the phone was not emitting as much radiation. As a result, the finding likely understates the effect. However, the authors were trying to avoid the confounding that would occur if a person is talking, which would also lead to increased activation.

Did they use different phones, with antennae in different places?
FROM TPP — They used the same type of phone for all patients, and the antenna was located at the bottom of the phone, closer to the mouth. So we can’t draw any conclusions about the area of the brain affected because cellphones vary in where they position the antenna and users vary in how they hold the phone.

Glad you recognize the frequency ranges that are technologically occupied to induce brain changes externally (from without). But don’t you know that if you speak up about it, it’ll be attributed to an auditory hallucination, and you’ll get locked up? So, the health hazard especially is say if the external stimulus is telling your daughter to get herself knocked up in a sandwich, rather than something mysterious! Or worse, telling a modern day charlie manson to mobilize African gangs and to cause havoc in Lybia. Now, who is dying to take that role? What’s been happening to them? And who is pretending to put money on the table toward the former? And what’s been happening to them? Is it more valuable to let these jackasses expose themselves for the heavy readers to wake up and accept responsibility for real things that happen but are attributed to conspiracies by conventional wisdom) or, just to zap them out on and chalk it up to statistics of breast cancer, lymphoma or whatever.

The article says that (a) an increase in brain glucose metabolism occurs when an ‘active’ cell phone antenna is near the head and (b) “an increase in brain glucose metabolism happens during normal brain function.”

So perhaps having a cell phone next to one’s head is like *exercise* for the brain … If so, what we need are higher-powered cell phones!

. . . . .

One thing to keep in mind is that many young people talk on their cells phones very little, and mainly use them for texting. So perhaps the greatest risk (or gain) from cell phone use relates to older users.
FROM TPP — You’re definitely right about young kids and texting. Your point about normal brain activation is interesting and addressed somewhat in the story. It’s true that normal activity like talking activates the brain glucose metabolism. The question is whether artificial stimulation of this over an extended period of time has a detrimental effect. But to your other point — if there is no harm from this then the question is whether this technology can be used in patients who might benefit from additional activation and whether there is therapeutic potential.

Yet another study referenced behind a paywall — in other words, unless you pay, you can’t read.

The free abstract, extreme short and spare, concludes: ‘This finding is of unknown clinical significance. ‘

They do not test turning on the left phone on half the cohort, to ensure they are not just getting a ‘worry reaction’ or something else spurious.

When this experiment is attempted to be replicated by someone who is not already convinced that cell phone use causes harm (as these researchers seem to be), they might try that, and see if this very small effect on brain activity disappears.

If anyone can see the asymmetry in the heat map on the right, please indicate where you find it. I can’t see any, at least on my monitor. I hope that some other data, or some analysis of the data represented in this figure, substantiates the author’s claims and justifies the reviewers’ accepting the paper – but given that this is the figure chosen to demonstrate the authors’ results, and that they designed the figure and decided how to false-color it, I would have expected it to exemplify their findings. It doesn’t obviously do so, and I am suitably underwhelmed.

PS I don’t know why, but your hyperlink to the study isn’t working as a hyperlink for me. I can copy it, and paste into a new tab, and thereby get the study – but clicking it does nothing useful.

FROM TPP — I’ll check the link. The increased activity is on the far right side of the slide — you should see some reddish areas that show increased activation.

If cell phones have any effect, harmful or otherwise, on the brain, the effect is so weak that epidemiological and other studies so far have been unable to confirm it. Contrast this with studies showing smoking causes cancer and obesity causes type 2 diabetes. Giving up smoking, being physically active and keeping weight under control will have far more health benefits than getting a bluetooth headset for one’s mobile phone.

Great. Now that they’ve figured out that the human brain is sensitive to cell phone signals, how long will it be before they devise a system where the brain will receive messages without a cell phone at all? Brand name: Intuition.

Does not cause cancer (i e brain tumors). But what about opening of blood-brain barrier to harmful and/or detrimental substances? Industry says: “no cancer” – thereby removing focus from other possible dangers of cell phone use that perhaps are more threatening to our health. Poisoning of brain and accelerated cell death could be a real problem.

Very interesting. I wonder if anybody has studied the affects of using a bluetooth-equipped earpiece upon the brain? Does anybody have any idea how electromagnetic signature given off by a bluetooth device compares to a standard cellphone?

According to data from BlackBerry-maker Research in Motion (RIMM ), SARs for GSM BlackBerry devices (those sold by Cingular and T-Mobile in the U.S.) fall in the range of 0.25 watts per kilogram when used at your ear.

Bluetooth radios operate at much lower power levels than phones so, not surprisingly, the radiation added by a Bluetooth headset is insignificant by comparison. A study by William G. Scanlon of Queen’s University in Belfast found that a typical Ericsson (ERICY) Bluetooth radio module generates an SAR of just 0.001 watts per kilogram.

i believe the study and its findings were conducted and recorded properly, and that the information is important. however, i don’t think the study went far enough. i would have liked to see the results of a scan where both phones were turned on and one phone silently played the recorded message on one ear; or a scan with the phone on the right ear turned on but not playing recorded message, and the phone on the left ear remaining turned off. just curious.

As someone who’s subjected to inane cellphone calls all the time, I think it would be good if cellphone use does cost the user, and not just everyone else.

Why doesn’t the NIH study the effects of being trapped in close quarters with oblivious and obnoxious callers? I understand the MTA is going to enable cellphones in stations soon, and I can only imagine the fun that’s going to be.

What about headphones? One researcher is quoted as saying that an earpiece is safer than a phone, for surely the phone produces more radiation, but what of the effects of having an earphones in for extended periods of time? That is a study I would be interested in viewing the results of.

While this study is certainly interesting, it is probably difficult to interpret much beyond the sole fact that activity increased in one side of the brain and not the other.
FROM TPP — Ear pieces emit a tiny fraction of the already low-level of radiation coming out of the cellphone. See my response in comment 16.

More fuel for the Luddites’ fire…. Perhaps we should all live in caves and communicate via smoke signals. Then again, there’s that pesky risk of smoke inhalation.

There are much better things in life to worry about than cell phone radiation. If you’re a hypochondriac, don’t use one. If, like the majority of people, you’re not convinced that increased brain activity is a death sentence, you can now return to your regularly scheduled programming.

FROM TPP — I agree with you that there are known health risks — smoking, driving without a seatbelt, obesity — that are cause for greater concern. But given the ubiquity of the cellphone, and the money cellphone companies are making from their product and service, it seems appropriate to ask for more definitive study of the issue, particularly as it relates to young children.

Just like cigarettes, this is just the beginning of studies showing effects of holding an electronic transmitter near your brain. I know of more than one physician who has studied cell phone emissions and vastly cut back on use. I see people who cannot get OFF the stupid things and I can foresee them having some medical issues in the future.

I’d love to believe this hypothesis – that an active cell phone antenna increases nearby brain metabolism – but the data presented in this paper are hardly convincing.

According to the data in Table 2, the 95% confidence interval is so broad that the authors cannot be 95% confident that brain metabolism increases in the specified regions during cell phone use. The fold change is between 0.67 and 4.2 – which suggests there might be a decrease or an increase or no effect; the data are inconclusive. The only way that the authors show significance is by performing a statistical normalization that considers each region’s metabolism as a percent of overall brain metabolism. But since the absolute brain activity in the region isn’t significantly greater, then it’s inaccurate to say that the phone antenna is activating nearby brain metabolism.

A further problem: according to the PET scans shown in Figure 2, all regions of the brain are more active when a phone is “on” than “off”. On first glance, this looks like a really interesting finding! But it is in contradiction to the authors’ claim in the Results section, which begins, “Whole-brain glucose metabolism did not change significantly between conditions…”. If that sentence is correct then the authors should have shown a different patient as “representative of the study population”.

Between the imprecise statistical results and the figures that don’t support the text, this paper warrants a lot more caution.